(1) Field of the Invention
This invention relates to processing asphaltic compositions arising from tar sands and petroleum sources. More particularly, this invention involves processing asphalt compositions by means of air oxidation to produce useful materials suitable for industrial asphalt applications. By "industrial asphalt applications" is meant applications in which asphalt is used to produce protective or waterproofing coatings or sealers such as canal, ditch and pond linings; asphalt coated pipe; asphalt impregnated and coated building board; and most importantly, the production of roofing materials.
(2) Prior Art
The production of oxidized asphalt by blowing air through petroleum residue or straight run asphalt at elevated temperatures is well known in the art of petroleum refining. Such a procedure has a decided effect upon the physical properties of asphalt. In general, this technique serves to increase the hardness, softening point, pliability and weathering resistance of an asphalt and decreases its ductility and susceptibility to changes with temperature. Oxidized asphalts show better pliability than straight reduced products, when both are of equal hardness. It is to be noted that the hardness of the straight run asphalt may be greatly increased by extensive steam or vacuum distillation of the asphalt, but the resulting product is more susceptible to temperature than an air-blown asphalt.
The air-blowing technique, in comparison with the vacuum distillation method, is capable of producing an asphaltic product of greater pliability but of the same hardness as the asphaltic product produced by vacuum distillation of the same straight run asphalt. As a result of their very desirable hardness, pliability and weathering resistance qualities, oxidized asphalts have become popular in the production of roofing asphalts, protective coatings, electrical insulating compositions, molded articles, and the like.
Air-blowing in the presence of certain catalysts has been found to increase the rate at which the improved asphaltic properties can be achieved, and in some cases, modified the resulting product to have better properties than could otherwise be achieved by air-blowing without such catalysts.
It is well known that asphaltic compositions can be air blown to higher softening points; however, in doing so the needle penetration may be lowered below an acceptable value for some applications.
In U.S. Pat. No. 4,000,000 (1976), there is disclosed a process for recycling asphalt-aggregate compositions by heating and mixing with a desired amount of petroleum hydrocarbons having at least 55% aromatics.
In U.S. Pat. No. 2,287,511 (1938), there is disclosed an asphalt manufacturing process which involves heating a residuum in the presence of the following catalysts: ferric chloride, aluminum bromide, aluminum chloride, aluminum iodide; halides of copper, tin, zinc, antimony, arsenic, boron, titanium; hydroxides of sodium and potassium; calcium oxides, sodium carbonate, and metallic sodium. The catalysts are present in the asphalt composition in the absence of any injected air. There may be an air injection prior to the addition of the above-cited polymerizing catalysts but no air is injected when the catalysts have been added to the composition. That no air is added when the catalysts are present is clear from claim 3 of the U.S. Pat. No. 2,287,511 where it claims a process for making asphalt which involves a petroleum residuum in the absence of an added catalyst and then, in the absence of injected air, thickening the material to asphalt-consistency by heating with temperature rise in the presence of small amounts of an aluminum chloride catalyst.
In U.S. Pat. No. 2,370,007 (1943), there is disclosed a process for oxidizing asphalt involving air blowing a petroleum oil in the presence of a relatively small amount of certain types of catalysts. These catalysts involve an organic complex of a metallic salt. Examples of organic complexes of metallic salts may be obtained from sludges obtained in treating petroleum fractions with metallic salts such as metallic halides, carbonates and sulfates. The sludge obtained in treating a cracked gasoline with aluminum chloride was disclosed to be particularly suitable in accelerating the oxidation reaction and in producing an asphalt of superior characteristics. Also, hydrocarbon stocks from which the organic complex of metallic salts may be produced, were disclosed to include various hydrocarbon fractions containing hydrocarbons which are reactive with the metallic salts in particularly containing olefinic hydrocarbons. Sludges obtained by treating olefins with aluminum chloride were disclosed to be useful for the inventive process disclosed. Other sludges that were indicated to be particularly useful were obtained in the isomerization of hydrocarbons such as butane, pentane and naphtha in the presence of aluminum chloride. Sludges are obtained in the alkylation of isoparaffins with olefins in the presence of such alkylating catalysts as boron trifluoride and the like.
The summary of the metallic halides found to be particularly suitable to treat hydrocarbons to produce organic complexes of the metal salts for U.S. Pat. No. 2,370,007 are as follows: halides of aluminum, zinc, iron, boron, tin, copper and antimony with aluminum chloride being particularly preferred.
In U.S. Pat. No. 2,906,687 (1959), there is disclosed an improvement over conventional methods of air-blowing petroleum asphalts such as those employing modifiers for air blown asphalts which include ferric chloride, zinc chloride and particularly phosphorous compounds such as phosphorous pentoxide and stable phosphorous sulfides. The improvement involves using the reaction product of certain oxygenated organic compounds with conventional asphalt oxidation catalysts, in particular phosphorous pentoxide.
In U.S. Pat. No. 3,126,329 (1964), there is disclosed a blow bitumen which involves a residual petroleum fraction contacted with oxygen in the presence of an anhydrous solution of phosphorus pentoxide and phosphoric acid.
In U.S. Pat. No. 3,440,073 (1969), there is disclosed a purification process for asphaltic material wherein objectionable colors and odors are reduced by steam treating and adding water soluble inorganic alkali materials such as sodium hydroxide, sodium carbonate and potassium hydroxide. The water solutions of the water-soluble inorganic alkaline materials suitable for use in the disclosed invention have a pH of at least 8. Among the materials that would give rise to such solutions by way of an example include alkali metal, and alkaline earth metal compounds, notably their hydroxides carbonates and borates. The improved low level odor asphaltic products of the present invention were produced by incorporating into the hot asphaltic materials, preferably during the air-blowing, a water-soluble inorganic alkaline material in the form of a water solution.
In U.S. Pat. No. 2,421,421 (1944), there is disclosed a process for improving the activity of chlorides of certain metals such as zinc, iron, copper and antimony to increase the penetration and reduce the time of blowing an asphalt, pitch or a mineral lubricating oil. It was disclosed that the activity of halide salt catalysts were enhanced by the addition of a small portion of certain metallic powders, preferably in a very fine state of subdivision. Examples of some of the metals disclosed are aluminum, magnesium, copper, zinc, tin, iron, molybdenum, manganese and antimony.
In U.S. Pat. No. 2,317,150 (1943), there is disclosed a composition comprising a blend of an oxidized precipitated asphalt having a high asphaltene content of 45% to 65% plus a suitable flux capable of forming a complete and stable dispersion. Such fluxes usually contain a high aromatic content. An example of the suitable flux would be a mixture of heavy extract and a lubricating oil distillate. Precipitated asphalts are disclosed to be obtained in general from asphaltic crudes that have been freed of their lightest components by distillation.
In U.S. Pat. No. 2,276,155 (1939), there is disclosed a process comprising separating an asphalt fraction into components comprising asphaltenes, resins and an oil, and subsequently blending the oil with the asphaltenes in desirable proportions to yield a feedstock to be air-blown into a finished product. The term "asphaltenes" is defined to be those components of topped residuum which are insoluble in propane and insoluble in petroleum ether. The term "resins" includes those constituents of topped residuum which are insoluble in propane but soluble in petroleum ether. The term "oil" comprises those components present in topped residuum which are soluble in both propane and petroleum ether.
In U.S. Pat. No. 1,782,186 (1929), there is disclosed that air oxidation of asphaltic materials is changed and accelerated to a remarkable degree by the addition of small quantities of chlorides, sulfates or carbonates of zinc, iron, copper or antimony to the asphaltic material prior to air-blowing.
In U.S. Pat. No. 2,179,208 (1939), there is disclosed an improved process for manufacturing asphalts which comprises the steps of air-blowing a petroleum residuum in the absence of any added catalysts while maintaining the temperature at about 149.degree. to 260.degree. C. (300.degree. to 500.degree. F.) and then heating the material at a temperature at least about 149.degree. C. (300.degree. F.) with a small amount of a polymerizing catalyst. Examples of such polymerizing catalysts include chlorosulphonic, phosphoric, fluoroboric, hydrochloric, nitric or sulfuric acids and halides as ferric chloride, aluminum bromide, chloride, iodide, halides similarly of copper, tin, zinc, antimony, arsenic, titanium, etc. hydroxides of sodium, potassium, calcium oxides, sodium carbonate, metallic sodium, nitrogen bases, ozonides and peroxides. Blowing of air may be continued in the presence of the polymerizing catalysts.
In U.S. Pat. No. 4,202,755 (1980), there is disclosed a process for making pitch from petroleum bottom fractions by air-blowing in the presence of metallic sodium. Potassium metal is also expected to catalyze the same reactions as sodium but is disclosed to be so much more reactive as to be far less desirable.
In U.S. Pat. No. 3,607,334 (1971), there is disclosed an asphaltic composition comprising as a major amount of asphalt and a minor amount of a second pass foots oil derived from heavy lube distillate. The second pass foots oil is derived from deoiling slack wax removed from heavy lube oil distillates in the manufacture of high viscosity distillate lubricating oils. The foots oil comprises, in general, about 55 to 65 wt% in paraffins, about 0 to 4 wt% isoparaffins, about 30 to 45 wt% naphthenes and about 1% aromatics. The compositions described above can be used as a felt saturant and also as a starting material in the air-blowing process for making roofing material.
In U.S. Pat. No. 4,052,290 (1977), there is disclosed an improved asphalt composition made from a blend of marginal asphalt stock and coal-derived asphaltenes. The blended composition is then air-blown to a final product. Conventional air-blowing conditions are asserted to be described in U.S. Pat. Nos. 2,767,102; 3,462,359; and 3,707,388. In a typical air-blowing procedure, an air rate of about 1.2 to 3.5 cubic feet per hour per pound of charge is employed under atmospheric pressure at a temperature in the range of between about 204.degree. C. (400.degree. F.) to about 427.degree. C. (800.degree. F.).
Efforts to understand the detailed chemistry behind air-oxidation of asphaltic compositions or fluxes to produce useful asphaltic materials has been almost totally frustrated by the complexity of the various molecular species present. The difficulties are further compounded by the varieties of crude sources from which asphaltic fluxes can be derived.
To properly understand the discussion of the instant invention, the following definitions are useful:
An "asphaltic flux" or "flux" throughout this Specification and claims means a low viscosity asphaltic material which is used as the oxidizer charge. The flux is produced by blending various residual streams with other streams of high boiling point to produce a flux of the desired consistency and composition.
An asphaltic flux for purposes of this invention is intended to mean a composition comprising at least four components. These four components are "asphaltenes", "polar", "aromatics", and "saturates", each of which is defined for purposes of this invention to be fractions isolatable in accordance with procedures set out in detail in EXAMPLE ONE. These fractions are similar to but not identical to some of those discussed in U.S. Pat. No. 2,276,155 (1939).
"Slack wax" for purposes of this invention is a product produced during the refining of lubricating oils. A material called a waxy distillate is distilled from a crude oil and extracted with furfural to remove aromatic compounds. After the furfural extraction, the raffinate from that extraction is treated with toluene and methyl ethyl ketone. The raffinate, toluene, and methyl ethyl ketone mixture is cooled causing a wax to crystallize. That wax isolated by filtration is called "slack wax". Other methods for "slack wax" production are known, but the above is simply an example. Some literature references to the production of slack wax are Petroleum Products Handbook; Virgil R. Guthrie, Editor; First Edition; McGraw-Hill Book Company, Inc.; 1960; Section 1, Page 26.
"Deasphalted oil" for purposes of this invention is derived in refinery operations from the overhead product of solvent deasphalting of a vacuum resid. Some literature references to the production of deasphalted oils are Petroleum Products Handbook; Virgil R. Guthrie, Editor; First Edition, McGraw-Hill Book Company, Inc.; 1960 Section 1, Page 23. Asphalt Its Composition, Properties, and Uses; Ralph N. Traxler; Reinhold Publishing Corporation; 1961 Chapter 7 Pages 129-130. Deasphalted oils are a mixture of "aromatics", "saturates" and a small amount of "polars".
"Petrolatum" for purposes of this invention means the waxy material produced as a by-product of bright stock production. Bright stock is a high visiosity lubricating oil. Petrolatum is simply the slack wax of bright stock production. Examples of methods for producing petrolatums can be found in Petroleum Products Handbook; Virgil R. Guthrie, Editor; First Edition; McGraw-Hill Book Company, Inc; 1960; Section 1, Page 26.
"Hydrocarbyl species" for purposes of this invention comprise at least about 20 carbon atoms, and more preferably at least about 30 carbon atoms, and still more preferably at least about 40 carbon atoms. "Hydrocarbyl" means throughout this Specification and claims a material consisting essentially of carbon and hydrogen with less than 10% by weight of carbon atoms involved in unsaturation, i.e., multiple bonds between carbon atoms. Preferably, the hydrocarbyl species is highly branched as opposed to being primarily linear. By "highly branched" is meant that there is at least 10% by weight, as based upon the total weight of the hydrocarbyl species, of tertiary carbon atoms, i.e. carbon atoms having at least three other carbon atoms attached to it. The only limitation on the number of carbon atoms in the hydrocarbyl species is sufficient boiling point and solubility. If there are too few carbon atoms then the hydrocarbyl species will be too volatile and will be distilled from the oxidizer during the oxidation process and if there are too many, then the hydrocarbyl species will be of too high a molecular weight and insoluble in the asphaltic material.
The presence of other atoms other than carbon and hydrogen does not change the usefulness of a hydrocarbyl species, provided these other atoms are present at less than about 10% by weight, as based upon the total weight of the hydrocarbyl species, preferably less than about 5% by weight, and still more preferably less than about 2% by weight. Examples of such other atoms include halogens, (e.g. fluorine, chloride, bromine amd iodine), sulfur, oxygen, nitrogen or mixtures thereof. Halogens, because of their corrosiveness, are preferably avoided.
Hydrocarbyl species include polymers such as polyethylene, polypropylene, polyisobutylene, polystyrene, polyesters, polyamines, and polyamides. Polyisobutylene has been found to work especially well.
"Cylinder stock" for purposes of this invention is a stream from a vacuum tower which is a cut above vacuum bottoms of a crude feedstock. Cylinder stock is obtained by the vacuum distillation of reduced crude. Cyclinder stock has a boiling point of 454.degree. C. to 560.degree. C. (850.degree. F. to 1040.degree. F.). Cylinder stock is separated by distillation under a pressure in the range of about 10 to 150 mm (millimeters of Hg) at a temperature usually in the range of from about 357.degree. C. to 399.degree. C. (675.degree. F. to 750.degree. F.). Use of cylinder stock as a blending component to marginal fluxes which are then upgraded by air oxidation to roofing asphalts is well known.
In the prior art, cylinder stock was used merely as a viscosity adjuster. There is no teaching or suggestion, how to use cylinder stock to transform an unsatisfactory flux to a useful roofing flux composition other than by trial and error, if at all.
"Satisfactory asphaltic roofing compositions" or "satisfactory roofing fluxes" for purposes of this invention are oxidizer charges or fluxes which upon air-oxidation in accordance with methods described with respect to examples in this Specification yield a material or asphalt suitable for use in (1) waterproof membrane construction, (2) dampproofing and waterproofing, (3) roofing applications, or (4) shingle coating.
With virtual invariability, if a flux can be air-oxidized with or without a catalyst to produce an asphalt suitable for use as a shingle coating, then that flux can be air-oxidized to an asphalt suitable for any of the other applications (1-3) cited above.
The following tables set out in detail the specification requirements that establish suitability for applications (1)-(4). In some applications, there are subclasses or types that fall within a board category, such as in roofing applications which can involve four subclasses or types.
______________________________________ (1) Waterproof Membrane Construction Property Minimum Maximum ______________________________________ Softening Point, .degree.C. (.degree.F.) 79 (175) 93 (200) Pen 25.degree. C. (77.degree. F.)/100 g/5 sec; 0.1 mm 50 60 Pen 0.degree. C. (32.degree. F.)/200 g/60 sec; 0.1 mm 30 -- Pen 46.degree. C. (115.degree. F.)/50 g/5 sec; 0.1 mm -- 120 Ductility, 25.degree. C. (77.degree. F.), cm 35 13 Flash, COC, .degree.F. 218 (425) -- Sol. in Trichloroethylene, wt. % 97.0 -- Loss on Heating, wt. % -- 1.0 Penetration after loss on heating, % of original 25.degree. C. (77.degree. F.)/100 g/5 sec; 60 -- 0.1 mm ______________________________________
__________________________________________________________________________ (2) Dampproofing and Waterproofing Type I Type II Type III Property Minimum Maximum Minimum Maximum Minimum Maximum __________________________________________________________________________ Softening Point, .degree.C. (.degree.F.) 46 (115) 60 (140) 63 (145) 77 (170) 82 (180) 93 (200) Flash, COC, .degree.F. 175 (347) -- -- 200 (392) -- -- 205 (401) -- -- Penetration 0.degree. C. (32.degree. F.)/200 g/60 sec, 0.1 mm 5 -- 10 -- 10 -- 25.degree. C. (77.degree. F.)/200 g/5 sec, 0.1 mm 50 100 25 50 20 40 46.degree. C. (115.degree. F.)/50 g/5 sec, 0.1 mm 100 -- -- 130 -- 100 Ductility, 25.degree. C. (77.degree. F.), cm 30 -- 10 -- 2 -- Solubility in 99 -- 99 -- 99 -- Trichoroethylene, wt. % __________________________________________________________________________ Asphalt in Roofing Type I Type II Type III Type IV Property Minimum Maximum Minimum Maximum Minimum Maximum Minimum Maximum __________________________________________________________________________ Softening Point, .degree.C. (.degree.F.) 57 (135) 66 (151) 70 (158) 80 (176) 85 (185) 96 (205) 99 (210) 107 (225) Flash, COC, .degree.C. (.degree.F.) 225 (437) -- -- 225 (437) -- -- 225 (437) -- -- 225 (437) -- -- Penetration 0.degree. C. (32.degree. F.)/200 g/60 sec, 0.1 mm 3 -- 6 -- 6 -- 6 -- 25.degree. C. (77.degree. F.)/100 g/5 sec, 0.1 mm 18 60 18 40 15 35 12 25 46.degree. C. (115.degree. F.)/50 g/5 sec, 0.1 mm 90 180 -- 100 -- 90 -- 75 Ductility, 25.degree.C. (77.degree. F.), cm 10.0 -- 3.0 -- 2.5 -- 1.5 -- Solubility in 99 -- 99 -- 99 -- 99 -- Trichloroethylene, wt. % __________________________________________________________________________ Shingle Coating - Different Specs by Each Company; This is Only An Average Minimum Maximum __________________________________________________________________________ Softening Point, .degree.C. 104 (220)F.) 113 (235) Flash, COC, .degree.C. (.degree.F.) 225 (437) -- -- Penetration 25.degree. C. (77.degree. F.)/100 g/5 sec, 0.1 mm 17 23 Solubility in 99 -- Trichloroethylene, wt. % __________________________________________________________________________
"Air oxidation without catalysts" for purposes of this invention means the bubbling of an oxidizing gas, usually air, through an asphaltic flux at an elevated temperature of 149.degree. C. to 427.degree. C. (300.degree. F. to 800.degree. F.) in the absence of an oxidation catalyst. The oxidation causes the flux to increase in consistency thus yielding a finished asphaltic material with a fairly high softening point.
"Air oxidation with catalysts" for purposes of this invention means the bubbling of an oxidizing gas, usually air, through an asphaltic flux at an elevated temperature of 149.degree. C. to 427.degree. C. (300.degree. F. to 800.degree. F.) in the presence of an oxidation catalyst. The presence of the oxidation catalyst alters the course of the oxidation and yields a product with different properties than would have been obtained without the catalyst in usually a shorter amount of time. Examples of catalysts found to yield preferred results are materials which contain carbonate or sesquicarbonate or mixtures thereof, e.g. alkaline earth carbonates and sesquicarbonates. However, other well known prior art catalysts for accelerating air oxidation of asphaltic roofing fluxes usually will also work. Examples of such other catalysts are ferric chloride and phosphorus pentoxide. The principal requirement for such oxidation catalysts is dispersibility throughout a flux.
"Compounding" for purposes of this invention means any method which can be used to mix various asphaltic flux blending streams to obtain a homogeneous blend. The compounding will almost always be done while the streams are in the liquid state and will usually involve some form of mixing although any method which will yield a homogeneous blend is acceptable.
An "unacceptable asphaltic roofing flux" comprising asphaltenes, polars, aromatics and saturates (as hereinabove defined) is one which after air oxidiation with or without catalysts fails to achieve those properties required of "satisfactory asphaltic roofing composition" or "satisfactory roofing flux".